1. Field of the Invention
The present invention relates to an organic light emitting display, and more particularly, to a pixel capable of displaying an image with uniform brightness, an organic light emitting display including the pixel, and a method of driving the same.
2. Description of the Related Art
Recently, various flat panel displays (FPD) capable of reducing weight and volume that are disadvantages of cathode ray tubes (CRT) have been developed. The FPDs include liquid crystal displays (LCD), field emission displays (FED), plasma display panels (PDP), and organic light emitting displays.
Among the FPDs, the organic light emitting displays display images use organic light emitting diodes (OLED) that generate light by re-combination of electrons and holes. The organic light emitting display has high response speed and is driven with low power consumption.
A conventional organic light emitting display includes a data driver for supplying data signals to data lines, a scan driver for sequentially supplying scan signals to scan lines, a pixel unit including pixels arranged at intersections of the data lines and the scan lines, and a timing controller for controlling operations of the data driver and the scan driver.
When the scan signals are supplied through the scan lines, the pixels charge voltages in correspondence to the data signals supplied through the data lines in storage capacitors included in the pixels and supply currents corresponding to the charged voltages to organic light emitting diodes (OLED) to emit light components with brightness components corresponding to the data signals.
In a conventional pixel, a threshold voltage of a driving transistor is shifted by a voltage applied in a previous frame period. Therefore, when a high voltage is to be charged in a storage capacitor in the previous frame period and a low voltage is to be charged in the storage capacitor in a current frame period, for example, when a white gray scale is to be realized in the current frame period after a black gray scale is realized in the previous frame period, a desired voltage may not be charged in the storage capacitor. That is, the gray scale to be displayed in the current frame period is affected by the gray scale displayed in the previous frame period so that the pixel displays an image with non-uniform brightness. Therefore, an after image may be generated in an image displayed by the pixel unit.